Solids having improved electrical conductivity



United States Patent 3,226,321 SOLIDS HAVING IMPROVED ELECTRICALCONDUCTIVHTY John P. McDermott, San Diego, Calif., assignor to EssoResearch and Engineering Company, a corporation of Delaware No Drawing.Filed Dec. 17, 1962, Ser. No. 244,874 7 Claims. (Cl. 2528.8)

This application is a continuation-in-part of pending application SerialNumber 82,692, filed January 16, 1961.

The present invention relates to the use of organic phytates andparticularly to the use of organic nitrogen base phytates to improve theelectrical properties of solid materials Which have a tendency togenerate, accumulate, or retain electrical charges.

There has been a growing need and urgency for effective materials to aidin improving the electrical properties of nonconductive solid materialsthat have a tendency to generate, accumulate or retain electricalcharges on their surfaces. In particular, the generation and/oraccumulation of electrical charges on hydrophobic nonconductivematerials such as synthetic materials, plastics, resins, rubbers, andtextile fibers has been a vexing problem. The quantity and seriousnessof the charges depend in part upon the nature of the material, thetemperature, humidity, and the like. The hydrophobic nature of syntheticfabrics and textiles or their blends with natural animal and vegetablefibers and materials has hampered their effectiveness and fullcommercial use. The tendency of these synthetic textiles to generate andaccumulate electrical charges renders their handling and processinghazardous by virtue of the danger of electrical discharges. Further,electrical charges accumulated on these materials have a pronouncedtendency to attract dust and other deleterious material having anopposite charge.

Attempts to remedy and rectify the foregoing problem have prompted theuse of radioactive metal bars to neutralize the charge by ionizing theatmosphere near the charged surface, by the use of conductive coppertinsel or other grounding means in contact With the charged surface, andthe like. The subsequent employment of synthetic materials as textilefabrics has resulted in the Well known clinging effect by virtue of thestatic charges on the materials. This clinging effect is particularlynoticeable on the human body after certain motion has generated a chargeon the fabric surface or by the attraction of other materials after asynthetic fabric has been tumbled, such as in a dryer. Attempts to solvethis problem have utilized certain additives on the surface of thefabric or material to promote electrical conductivity, and thus aid indissipating the charge before an excessive charge is allowed toaccumulate. These additives have not proven to be entirely satisfactoryor practical in that some are readily susceptible to removal onlaundering of the fabric or on contact with Water, or alter the feel orsurface of the fabric and the like.

It is an object of this invention to provide a class of additives whicheffectively dissipate electrical charges generated on solid materialssuch as fabrics.

The object of this invention is attained through the use of organicphytates, particularly organic nitrogen base phytates, and preferablyorganic ammonium phytates. These materials may be described morespecifically as hydrocarbyl ammonium phytates. These phytates are formedby the reaction of an acidic phytate with a basic organic nitrogencompound to yield an organic nitrogen base phytate. The nitrogen baseradical comprises a nitrogen atom having four substituent groups, atleast one group being an organic radical with the ammonium nitrogen atomsubstituent groups being selected from the class ice consisting ofhydrogen and organic radicals. The organic radicals are preferablydirectly bonded to the nitrogen atom by a carbon atom of an organicradical, and especially an organic radical having from 1 to about 30carbon atoms.

The aliphatic ammonium phytates are the preferred materials of theinvention with the oil .soluble teritary ammonium phytates particularlypreferred, while a mixed tertiary and quaternary ammonium phytateprepared by the neutralization of phytic acid With a tertiary amine anda quaternary ammonium hydroxide mixture being especially preferred.

The organic nitrogen base phytates of the invention may be prepared byreacting phytic acid or an acidic phytate salt such as calcium phytateor ammonium phytate, or an acidic partial ester or acidic metal phytatecomplexes, such as alkaline earth or heavy metal complexes, and thelike, or preferably phytic acid With a basic organic nitrogen basecompound. The preferred method of preparation is the reaction of phyticacid with a basic amine or a quaternary ammonium compound. The resultingwater from the reaction or from the phytic acid concentrate may beremoved by means of an azeotropic distillation employing an organicsolvent such as benzene, toluene, hexane and the like. The reaction ofphytic acid and a quaternary ammonium compound is an acid base type ofdisplacement reaction. Thus, the reaction of phytic acid with quaternaryammonium hydroxide yields the desired quaternary ammonium phytate andwater of the reaction. The reaction of phytic acid and an amine is anaddition type of reaction with theoretically no byproduct of thereaction obtained. Both reactions will yield the nitrogen base organicammonium phytates of the invention. The organic ammonium phytates of theinvention are believed to be phytates composed of a positively chargednitrogen base cation and a negatively charged phytate anion. The numberof cations in the molecule may be varied from 1 to 12, depending uponthe number of acidic hydrogen atoms removed from the acidic phytateanion.

The ratio of the acidic phytate to the basic organic nitrogen compound,e.g. phytic acid to quaternary ammonium hydroxide or amine, may bevaried widely. Depending upon the ratio of the reactants employed, theorganic phytate salt formed may have from, 1 to 12 basic ammoniumradicals. In general, it has been found that the salts containing fromabout 1 to about 6 quaternary ammonium groups are somewhat moreeffective than the more fully substituted salts. The use of themono-substituted to hexa-substituted phytate compounds for promotingelectrical conductivity is therefore preferred.

The quaternary ammonium hydroxides which are employed in preparing thequaternary ammonium phytates include those hydroxides wherein organicradicals attached to the central ammonium nitrogen atom may besubstituted or unsubstituted, aliphatic, alicyclic, heterocyclic,aromatic, or arene radicals, including alkylaryl and arylalkyl, of from1 to about 30 carbon atoms, or combinations thereof. These organicradicals may have substituent groups such as hydroxyl, sulfhydryl,halogen, ether bound oxygen, acetylenic groups, nitro, sulfur, sulfoxy,and the like. Due to economic availability, present cost, and electricalcharacteristics, the tetra-aliphatic quaternary ammonium hydroxides arethe preferred reactants of the quaternary ammonium hydroxides. Thesubstituent groups may be alkyl, alkenyl, alkynyl, cycloalkane, andcycloalkene radicals of from 1 to 30 carbon atoms, or combinationsthereof.

Examples of suitable quaternary ammonium phytates prepared by reactingphytic acid with quaternary ammonium hdroxide include tetramethylammonium phytates, tetrapropyl ammonium phytates, methyltributylammonium phytates, dimethyldibutenyl ammonium phytates,isopropyltrihexyl ammonium phytates, diethyl dihexadecyl ammo-niumphytates, dimethyldioleyl ammonium phytates, trimethyloleyl ammoniumphytates, butyltrioleyl ammonium phytates, dibutyldicyclopentyl ammoniumphytates, tetrah'eptadecyl ammonium phytates, tetraeicosyl ammoniumphytates, dimethyl benzyl soya ammonium phytates, triethyltolyl ammoniumphytates, trimethylcyclohexyl ammonium phytates, octadecyldimethylbenzyl ammonium phytates, l-ethylquinoliniurn phytates, trimethylphenylammonium phytates, l-ethylpyridinium phytates, cetyldimethyl benzylammonium phytates, tributyl-4-octynyl phytates, dimethylpropyl-4-nitrooctyl phytates, trimethyl-IO-mercaptooctadecyl ammonium phytates,dimethyldi-(l-chlorooctadecyl)ammonium'phytates, and the like.

All of the above salts may contain from 1 to 12 ammonium groups. Theespecially preferred quaternary ammonium phytates are those oil solublephytates having a mixture of lower alkyl groups and aliphatic groups offrom 8 to 18 carbon atoms, such as dialkyl dialiphatic C C phytates,wherein the aliphatic groups are derived from commercially availablesaturated and unsaturated fatty acid radicals. The basic nitrogencompounds useful in the preparation of the compounds may also includenitrogen compounds having substituent groups derived from naturallyoccurring materials such as from vegetables, animal and marine fats andoils like beef tallow, soybean, coconut, cottonseed, olive, linseed,palm kernel, corn, peanut, cod, whale, tung, lard, and the like. Thesefats and oils are mixtures of saturated and unsaturated enoic dienoicand dienoic fatty acids of from about 8 to 20 carbon atoms per molecule.Quaternary ammonium compounds and amines suitable for preparing theinventive phytates and containing fatty acid substituent groups as aboveare available from commercial sources. An example of a suitablecommercial tertiary amine is a methyl disoya amine wherein the soyaradical contains approximately 20 weight percent hexadecyl, 17 weightpercent octadecyl, 26 Weight percent octadecenyl, 37 weight percentoctadecadienyl and about 7 weight percent of other unidentifiedmaterial. Suitable commercial amines include those with a mean molecularweight of from 260 to about 530. Tertiary aliphatic amines having onelower alkyl group of from 1 to 6 carbon atoms and at least one longchain aliphatic group of from 8 to 18 carbon atoms, e.g. derived fromfatty acids, yield particularly effective oil soluble aliphatic tertiaryammonium phytates. Commercial amines would thus include methyl dioleylamines, methyl dihydrogenated tallow amines, dimethyl soya amine, ethyldisoya amine, methyloleyl amine, ethyl soya amine, dimethyl coco amine,and the like.

A suitable commercial quaternary ammonium hydroxide whose substituentgroups are derived from naturally occurring materials would be trimethylsoya ammonium hydroxide, dimethyl dicoco ammonium hydroxide, dimethylditallow ammonium hydroxide and the like. Quaternary ammonium compoundsand amines having one and preferably two or more of such naturallyoccurring fatty acid groups are generally less expensive and readilyavailable and therefore commercially preferred for preparing oil solublephytates.

The basic organic nitrogen radical of the ammonium phytates may also bederived from the reaction of an acid phytate, such as phytic acid, or apartially neutralized phytate, with a substituted or unsubstitutedprimary, secondary, or tertiary organic amine; diamines; polyamines;

hydroxyl amines; carboxylic amines; amidines; and the like. The aminesmay have substituted or unsubstituted, aliphatic, alicyclic, aromaticheterocyclic, or arene organic radicals of from 1 to 30 carbon atoms orcombinations thereof. Aliphatic amines, such as unsubstituted aliphaticamines having alkyl, alkenyl, and alkynyl radicals and mixtures thereof,and especially oil soluble tertiary aliphatic amines, are preferredmaterials.

Suitable amines include primary amines such as p,p dibutyldiphenylamine, 4-amyl-a-naphthyl amine, ethyl amine, sec butyl amine, allylamine, 2-amino ethanol, 2-phenyl ethyl amine, a-methyl benzyl amine,2-amino- Z-methyl-l-propanol, para-amino benzoic acid, toluidine.chloroaniline, urea, thiourea, octylamine, oleylamine, cyclohexylamine,benzylamine, p-methoxybenzylamine, p-anisidine, aniline,l-naphthylamine, p-aminophenol, octyl-p-aminobenzoate, p-octylaniline,and the like; secondary amines such as: di-isoamylamine, di-oleylamine,di-soya amine, di-cyclohexylamine, N-methylcyclohexylamine,di-phenylarnine, N-octyl- 1 -naphthylamine, N,N-bis-(t-octyl)thiourea,N-phenyl-N-t-octylurea, N- octylcyclohexylamine,N-(2-ethylhexyl)aniline, quinoline morpholine and alkyl morpholine, suchas N-methyl and Nethy1 morpholine, phenothiazine, dimethylpiperidine,piperidine, pyrrolidine, dihydrogenated tallow amine, pyrazole,pyrazoline, p-methylaminophenol, and the like; tertiary amines such as:tributyl amine, methyldisoya amine, methyldioleylamine,dimethyloleylamine, 2- diethylamino ethanol, tribenzylamine,N,N-diethylcyclohexylamine, N,N-dibutylaniline,di(2-ethylhexyl)ethanolamine, N-dodecylmorpholine, pyridine, B-picoline,pyrazine trioleylamine, N-octyl cyclohexyl amine, N-methy1-2-pyrrolidone, polyvinyl pyrrolidone, and the like; alkaloids such as:nicotine, morphine, quinine, papaverine, ephedrine, tropine, atropine,coniine, cocaine, brucine, and the like; polyamines, including diaminesand diamino dialkyl amines such as: heXamethylene-tetramine, ethylenediamine, 1,6-hexanediamine, p-phenylenediamine, N-oleylpropanediamine-l,3 piperazine, N,N'-dibutyl-pphenylenediamine,tetramethylethylene diamine, dimethylaminomethyl phenols, triamines likeaminoethyl piperazine, combining a primary, secondary, and tertiaryamine group in a single molecule, and the like; carboxylic amines oramino acids such as: aminoacetic acid, paminophenylacetic acid,4-aminobutyric acid, Z-amino hexanoic acid, and the like; azo aminessuch as: pdimethylaminoazobenzene-o-carboxylic acid, azobenzene,p-phenylazoaniline, and the like; guanidines and amidines such as:p-butylphenyl guanidine, phenyl biguanidine, benzoguanamine, triphenylguanidine, 1,3-di-0-tolyl guanidine, tetramethyl guanidine, formamidine,N,N- diphenyl formamidine, and the like; hydrazines such as: alkylhydrazine, aryl hydrazine and quaternary hydrazinium bases, hydrazine,phenylhydrazine, N,N-dimethyl- N-octadecylhydrazinium hydroxide,dimethyl hydrazine, and the like; hydroxyl amines or amino alcohols suchas: alkanol amines, triethanol amines, 3-diethyl amino-lpropanol,2-amino ethanol, l-amino-Z-propanol, 2-2- imino diethanol,2-amino-2-methyl-l,3-propane diol, 2- anilinoethanol, t-butyl aminoethanol, the alkyl alkanol amines like methyl ethanolamine, ethylethanolamine, ethyl diethanolamine, and the like; polyalkoxyl aminessuch as tripolyethoxy amine and the like.

It is seen that the preferred ammonium and amine compounds of thisinvention have :1 ON atomic ratio greater than 2/1, and preferably atleast 3/ 1. These ammonium and amine compounds are most effective whenreacted with the phytic acid in reducing electrical charge of the solidmaterials.

Phytic acid, the preferred reactant material to form the organicphytates of this invention is the hexaphosphoric acid ester of inositol.This compound has the formula:

O=P(OH)1 (6 OH 0 (HOMPOHC/ CHOl (OH)1 H I (HOhP OHC I HO P(OH),

CH O O=P(OH) Phytic acid Those organic ammonium phytates wherein theorganic nitrogen base is a mixture of an aliphatic quaternary ammoniumhydroxide and a tertiary aliphatic amine and particularly those having aquaternary to amine ratio of between 4:1 and 1:4, and preferably 3:1 to1:1, are especially preferred additives. For example, phytic acid may:be neutralized with a mixture of a dimethyldioleyl ammonium hydroxideand a methyl disoya amine to yield an effective mixture of ammoniumphytates.

The organic nitrogen base phytates of the invention are profitablyemployed in treating nonconductive solid material such as paper, rubber,plastics, resins, asbestos, wood, and synthetic fibers and textiles, andblends thereof in order to promote the electrical conductivity of thesurface. The textile fibers or other materials may be treated with theinventive phytates by brush, spray, dip, coating, impregnation, or otherconvenient means or techniques of application for treating the surfaceof the material to be protected with the desired phytate. The treatedmaterial may be synthetic plastics and resins in fiber, fabric, film,tube, or other form. Suitable synthetic textile fibers which would bebenefited by treatment with the phytates of the invention includearcylics, polyesters, polyamides, polyethylene, polypropylene, polyvinylchloride, glass fibers, and the like, and blends thereof with othermaterials such as Wool, cotton, felt, asbestos, and other ingredients.The phytate treatment may be beneficially accomplished in the presenceor absence of other finishing and testing materials, such as starch,wrinkle-proofing ingredients, res-in finishes, and the like.

The organic ammonium phytates may be successfully employed by treatingthe desired material so as to deposit a minor amount of the phytate onthe surface to be protected. Preferred methods of application includedipping or impregnating the item to be treated in a solution of avolatile liquid solvent such as an aliphatic or aromatic alcohol likebenzyl alcohol, isopropanol, ethanol; an ether anisole, ethyl ether; ahydrocarbon like toluene, heptane; a halogenated solvent likechloroform, perchloroethylene and the like; or combinations thereofwhich may contain from 0.1 to 10.0 weight percent of the desiredadditive and usually from 0.5 to 2.0 weight percent. In certain cases,direct contact by wiping the phytate directly or in admixture withparaffin or other filler materials directly on the surface isrecommended.

The exact nature and objects of the invention may be more fullyunderstood from the following examples.

Example 1 Quaternary ammonium salts of phytic acid were prepared byreacting dimethyldioleyl ammonium hydroxide with phytic acid in varyingamounts.

The quaternary ammonium hydroxide was added to a mixture of phytic acidin benzene, with stirring, in a flask equipped with a condenser andwater trap. After addition was complete, the reaction mixture wasdistilled until all the water was removed. The products, obtained onevaporation of the benzene, were cream-colored, waxy solids. Analysisshowed the salts prepared to be monodimethyldioleyl ammonium phytate,tri-dimethyldioleyl ammonium phytate, hexa-dimethyldioleyl ammoniumphytate and dodecyl-dimethyldioleyl ammonium phytate. Other quaternaryammonium phytates of the examples were prepared in a similar manner andalso mono-tetradecyl ammonium phytate.

Example 2 Other organic ammonium phytates were prepared by reacting atertiary aliphatic amine such as methyl disoya amine with phytic acid invarying amounts.

The mono-methyl disoya ammonium phytate was prepared by adding ten grams(about 0.014 mole active ingredient) of a methyl disoya amine commercialmixture to a stirred dispersion of 13.2 grams (0.014 mole) of phyticacid (70% solution in water) in benzene-xylene,

followed by azeotropic distillation to remove the water. Subsequentfiltration of the slightly hazy reaction mixture yielded a clearconcentrate of the mono-me-thyldisoya ammonium phytate in xylene inapproximately theoretical yield amounts. The mono-methyldisoya aminephytate will be hereafter identified as mono MZSA phytate. Other aminesalts, as in the examples, were prepared in a similar manner; and alsoprepared in this manner were mono-soya ammonium phytate, hexa-soyaammonium phytate, di-diethanol soya ammonium phytate, and di-dimethylsoya ammonium phytate.

Example 3 The ammonium phytates of the invention have been discovered tobe effective in promoting the electrical conductivity on the surfaces ofsolid materials such as nonconductive synthetic textiles, plastics, andthe like. When employed in treating the surf-ace of a nonconductivematerial, such as a textile fabric, the ammonium phytates do not alterthe appearance or feel of the treated surface and further are resistantto removal by laundering with aqueous detergents and soap, Watercontact, and dry cleaning solvents. The ammonium phytates may be appliedby dipping the item to be tested into a solution of the phytate in avolatile solvent followed by evaporation of the solvent, or may beapplied by wiping the pure additive material directly on the surface tobe tested, or by spraying from an aerosol can, or other convenientmethods of application.

To demonstate the efiicacy of the ammonium phytates in preventing staticgeneration arising from the frictional contact of solid surfaces, suchas textiles, plastics, rubber, and the like, a test was performedutilizing the Keithley electrometer. This instrument (Model 200) wasequipped with a Keithley static detector (Model 2005). The testmaterials used were twelve-inch square pieces of nylon jersey clot-h.

A piece of cloth was stroked several times with Lucite rod When thecloth was placed near the static detector, the meter needle jumpedbeyond the 10 volt meter scale in the negative direct-ion; when theLucite rod was placed near the static detector, the needle jumpedoff-scale in the opposite direction.

Example 4 The cloth, treated as described in Example 3, was dipped in a1.0% solution of di-dimethyldioleylammonium phytate in chloroform. Afterevaporation of solvent the above test was repeated. This treated clothshowed no activity-the meter needle remained at zero. The Lucite rod,however, was still active.

Example 5 A small amount of the pure dimethyldioleylammonium phytate(solvent-free) was rubbed on the Lucite rod of Example 4 after which itwas wiped with a clean cloth. The treated rod showed no static activityafter contact with untreated cloth.

Example 6 To determine the permanency of this additive treatment, onepiece of cloth, treated as described in Example 3, was Washed in hotAlconox solution, rinsed, and dried; another piece of treated cloth wasdipped in perchloroethylene and dried, six times. Neither cloth showedany static activity, indicating that the additive was still retained onboth pieces of cloth.

Example 7 A piece of cloth was dipped in a 1.0% solution of tri-(methyldisoya ammonium) phytate in isopropanol and then dried. The clothshowed no static activity in the tests described above. A Lucite rod,dipped in this solution and dried, also showed no static activity.

The foregoing test results demonstrate the remarkable properties of thesynthetic textile materials treated with organic ammonium phytates.

In summary, the applicant has discovered that a class of materials, theamomnium phytates, have particular utility in promoting electricalconductivity in treating nonconductive solid materials, in particulartextile fibers and fabrics. The preferred ammonium phytates are thoseoil soluble aliphatic ammonium phytates with the tertiary ammoniumphytates especially preferred, while mixed quaternary-tertiary ammoniumphytates are particularly preferred additives. It will be understoodthat modification within the skill of those adept in the art may be madewithout departing from the scope of the invention.

What is claimed is:

1. A solid synthetic hydrophobic non-conductive mate rial selected fromthe group consisting of fiber and cloth containing on its surface aminor amount sufiicient to promote electrical conductivity of saidmaterial of an organic ammonium phytate consisting of a negativelycharged phytate anion and 1 to 12 positively charged ammonium basecations wherein each of said cations consists of an ammonium nitrogenatom and 1 to 4 organic radicals bonded to said nitrogen atom bycarbon-to-nitrogen bond, each of said organic radicals containing 1 to30 carbon atoms.

2. A material as defined by claim 1, wherein said phytate contains 1 to6 of said cations and wherein each of said cations has acarbon-to-nitrogen atomic ratio of greater than 2: 1.

3. A material as defined by claim 1, wherein said organic radicals arealiphatic radicals.

4. A material as defined by claim 1, wherein said phytate ismethyldisoya ammonium phytate.

5. A material as defined by claim 1, wherein said phytate isdimethyldioleyl ammonium phytate.

6. A process for reducing the tendency of solid synthetic hydrophobicnon-conductive material selected from the group consisting of fiber andcloth to generate and accumulate electrical charges, which processcomprises coating the surface of said material with a minor amount,suificient to promote electrical conductivity, of an organic ammoniumphytate consisting of a negatively charged phytate anion and 1 to 12positively charged ammonium base cations wherein each of said cationsconsists of an ammonium nitrogen atom and 1 to 4 organic radicals bondedto said nitrogen atom by a carbon-to-nitrogen bond, each of said organicradicals containing 1 to carbon atoms.

7. A process for reducing the tendency of solid synthetic hydrophobicnon-conductive material selected from the group consisting of fiber andcloth to generate and accumulate electrical charges, which processcomprises coating the surface of said material with a volatile liquidsolvent containing dissolved therein about 0.1 to 10 wt. percent of theorganic ammonium phytate consisting of a negatively charged phytateanion and 1 to 12 positively charged ammonium base cations wherein eachof said cations consists of an ammonium nitrogen atom and 1 to 4 organicradicals bonded to said nitrogen atom by a carbonto-nitrogen bond, eachof said organic radicals containing 1 to 30 carbon atoms andsubsequently evaporating said volatile liquid solvent to thereby coatsaid material with said phytate.

References Cited by the Examiner UNITED STATES PATENTS 2,256,112 9/1941Dickey et a1. 252-8.8 XR 2,279,502 4/1942 Dickey et al. 2528.8

JULIUS GREENWALD, Primary Examiner.

1. A SOLID SYNTHETIC HYDROPHOBIC NON-CONDUCTIVE MATERIAL SELECTED FROMTHE GROUP CONSISTING OF FIBER AND CLOTH CONTAINING ON ITS SURFACE AMINOR AMOUNT SUFFICIENT TO PROMOTE ELECTRICAL CONDUCTIVITY OF SAIDMATERIAL OF AN ORGANIC AMMONIUM PHYTATE CONSISTING OF A NEGATIVELYCHARGED PHYTATE ANION AND 1 TO 12 POSITIVELY CHARGED AMMONIUM BASECATIONS WHEREIN EACH OF SAID CATIONS CONSISTS OF AN AMMONIUM NITROGENATOM AND 1 TO 4 ORGANIC RADICALS BONDED TO SAID NITROGEN ATOM BYCARBON-TO-NITROGEN BOND, EACH OF SAID ORGANIC RADICALS CONTAINING 1 TO30 CARBON ATOMS.